Machine for and method of folding sheets



Dec. 25, 1956 1.. BAKER ET AL MACHINE FOR AND METHOD OF FOLDING SHEETS Filed Jan. 24 1951 eel l 3 Sheets-Sh III/[ 111]! 00M 0. flaw ATTORNEY.

Dec. 25, 1956 L. BAKER ET AL MACHINE FOR AND METHOD OF FOLDING SHEETS mom a, 2 W .L N6, 6m 0 m 0 9h M M Q an w @E I w M w S 3 Y. B :i 2 L ZY ll 4 i 3 W/ E W W 3N SN m r3 5 MW .m. MN 3N @l 09 E 8O f v. OLRV E 08 SM 8N rfi 3N 9m gmmw 03 I. 1 m5 m5 3M E m m 7. f3 1 on ms 1 al. a, @TI gig g 1 a a E $3. J: I. w *9 im Q: m: 4 2 m. a J d F e m d fl n United States Patent 2,775,448 1 MACHINE FOR AND METHOD OF'FOLDI NG 'SHEETS Leonard 'Baker, Hillsdaley N. 1., andwalter'l-lolms'and' Leo- C. Williams, Pearl River, N. Y.,-assignors, by mesne assignments, to Miehle lrinting Press & Manufacturing 7 Company, Chicago, 111., a corporation of Delaware Application January 24, 1951, Serial No. 207,541 21 Claims. (Cl. 270-85) This. inventionrelates to the art of folding, and particularly to the folding of printed sheets'a plurality of times toproduce multi-page book,.magazine .or similar signatures. v

In the United. States Patent No. 2,232,152, granted February 18, 1941, there is disclosed. a paper folding anglethird fold of each signature forming the back or bindingedgethereof. While many of these machines are in. actual use at. the present time and. operating very satisfactorily and successfully at a reasonable fast speed consistent with accurate and reliable folding, the capacity of each of. said machines is limitedto foursixteen page signaturesfor each cycleof operation.

It is, therefore, one of the objects ofthe present invention to providean improvedafolding machineof the above. character whereby a substantial increase in" the output of multi-fold signatures per hour may be conveniently obtained. 1

Another object of the invention is to provide an improved folding machine of the' above character capable of producing multi-fold signatures each consistingof an increased number of'pages equal to two like signatures produced successively in existing machines of the same character.

Another object is to providean improved folding 50 thereafter folded together a plurality of times with one machine wherein two unfolded sheets are associated and of the folds at right angles'to another fold, to produce a closed head signature'having double the number of pages therein than'he'retofore possible;

Another object is to provide 'in'a folding machine of the above character novel means for feeding and associating a second unfolded sheet in spaced superposed rela-- tion with a first unfolded sheet for subsequent folding with the latter sheet a plurality-of times to produce a closed head signature having twice the number of'pa'ges thereinas compared to a single sheet folded in like manner.

Still-another object is to provide an improvedmethod of producing multi-fold closed head signatures from two associated sheets, whereby wrinkles or gussets in theinner leaves of the signatures are completely'avoided:

Another object is to provide an improved method of weakening 3 a sheet in the -regionw of the fold line ato eliminate wrinklingof thesametupon-subsequent fold--v ingthereofjnto a multi-fold closed head signature. a

A further object is to provide an :improved method. of and mechanism forforming a plurality of slits in a "ice sheet'spaced along and extendingin opposite directions across a fold line, wherebywrinkling of the sheetis completely eliminated .upon subsequent folding. thereof into a 'multi-fold closed head signature. V

A still further object .is to provide an improved folding machine for simultaneously-folding two'superposed:

sheets at least three timeswith one of the folds at right angles to the first fold to. produce -a thirty-two page. signature, and wherein" the outside sheet has formed,

therein a plurality of slits spaced along and extending lengthwise ofthe first .fold line to allow the leaves of said sheet to creep and. adjust themselves to the change.

in their relation eifected by the right angle fold and thereby eliminate wrinkling of the inner leaves of' the signature.

Another object is .toprovide an improved folding machine for simultaneously folding two superposed sheets. at least three times with one ofthe folds at right angles.

to the first foldto produce a thirty-two page signature,

and whereinthe. outside sheet has formed therein a plu-' rality of short slits spaced along and extending in opposite directions across. the line of the first fold to allow the leaves of said sheet to adjust themselves to the change in their relation effected-by the right angle foldand thereby eliminate wrinkling of the inner leaves. of the signature.

Still another object is to provide a registering-rnechw. nism ofnovel construction for side registering two sheets disposed at different levels simultaneously and independ-v ently of each other.

The above and further objects and novel features of the present invention will more fully appear. from the following detailed description when the sametis readiin I connectionwith the accompanying ,drawings. It is to be expressly understood, however, that the drawings are for the purposeof illustration only;and are not intended as a definition of limits of the invention.

In the, drawings, .Whereindike reference characters refer to like parts throughout the several views, it

Figs. 1 and. la .arelcomplementary side elevational views, partly insection, illustrating somewhatscheniatically' a folding, machine embodying the present invention and in operableassociation with dual feeders for producing multi-page signatures in accordance with the present invention, the frameworkof said folding machine, said feeders and the sheet conveying means being. omitted for purposes of clearer illustration;

Fig. 2 is a front. elevational view, partly in section,

of the .sheet slitting mechanism shown in Fig.1 looking, 1

from the right thereof;

Fig. 3.is a front.elevat1onal View, partly insection,

of the. sheet. registering and stopping mechanism shown in Fig. 1 lookinglfrom the right .thereof;

Fig. 4 is a fragmentary.side..elevat1onal.view showing theoperating means for the second set of drop rollers shown in Fig. 1; t V

Fig. 5 is a rear elevational view. on a slightly. enlarged scale of the two-sheet side registering mechanismshown in Fig. 1a,. i

Fig. 6 is a top plan view of .said side registering mechanism, certain of the parts. .having portions thereof broken away for'purposesof clearer illustration;

Fig. 7 is a side elevational view, partly. in section, of said sideregistering mechanism looking from the right of Figs. .5 and. 6;

Fig. 8 is a side'elevational view on an enlargedscale, partly in section, of a modified form of sheet slitting I device;

Fig. 9 is a front elevational view of .the sheetslitting device shown'in Fig.,8 with the die plate and sheet clamps removed;v

Fig. '10 is an enlarged detail perspective view of a signa-- Patented Dec. 25,' 1956 ture product produced by the folding machine; and

Fig. 11 is a similar view of another signature product produced by the folding machine.

Referring to the drawings, the present invention is herein illustrated, by Way-of example, as being embodied in a folding machine of the well-known and-existing Quad type shown in the United States Patent No. 2,232,152 hereinbefore referred to, whereby a substantial increase in the production of multi-fold signatures may be obtained by said machine. For the sake of simplicity and brevity in illustrating and describing the present invention, only that A portion of .said folding machine with which the present invention is actually concerned is herein illustrated. Reference may be had to the abovementioned patent for a more detailed and complete description of the construction of said folding machine. It is to be expressly understood, however, that this Quad type of folding machine is not to be construed as a limitation, since the present invention may also be embodied with equal advantages in other types of signature folding machines such as, for example, the well-known and existing Double Sixteen type wherein a single sheet is given a first transverse fold and then divided into two once folded sections and thereafter each section is given a second fold at right angles to the first fold and a third and final fold either at right angles to the second fold or parallel thereto, resulting in two sixteen page signatures. The embodiment of the present invention in the Double Sixteen type of folding machine will likewise result in a substantial increase in the output of multi-fold signatures.

In the illustrated embodiment, the numerals 15 and 16 (Figs. 1 and la) designate sheet feeders which are both of the continuous type and are arranged in tandem relation and at lower and upper levels, respectively, with the lower level feeder 15 disposed rearwardly of the upper level feeder 16. As is customary in this type of feeder, the sheets S1 for feeder 15 and S2 for feeder 16 are fanned out and loaded upon an upper board 17 having an endless belt conveyor 18 which advances the bank of sheets around a drum 19 and onto a lower feed-board 20 equipped with an endless belt conveyor 21. The conveyor'21 advances the bank of sheets along the feed-board 20 to the front or discharge end thereof. 7

As is well known, each feeder 15, 16 embodies many instrumentalities such as, combing -wheels or suction wheels for feeding the sheets one after another in timed relation therefrom, and tail clamps for holding the second sheet against movement with the outgoing first sheet, but as these are all conventional features and as they form no part of the present invention, they have not been shown in the present disclosure.

Each sheet S1 fed by the lower level feeder 15 passes over a fixed transverse bridge-plate 22 and between timed drop rollers 23 and driven conveyor tapes 24 that cooperate to feed said sheet from said feeder forwardly in a horizontal plane beneath the feeder 16 towardthe folding machine to be hereinafter described. The drop rollers 23 are journalled on arms 25 which are fixed on a trans versely extending shaft 26 that is rocked by a cam 27 at predetermined intervals to raise and lower said drop rollers in timed relation with feeding of the sheets S1 into the machine. The cam 27 is fixed on a cam shaft 28 which forms part of the feeder 15 and is suitably driven to make one complete revolution for each cycle of operation of the machine. Cam 27 engages a roller 29 which is journalled on an arm 30 fixed on the rock shaft 26. When a sheet S1 is fed onto the tapes 24 by the lower level feeder 15, the drop rollers 23 are in raised position effected by'thecam 27 whereupon they are immediately lowered by a spring (not shown) to assist said tapes in feeding said sheet toward the folding machine.

The tapes 24 pass around a rear transversely extending driven roller 31 and around a front transversely extending idler roller 32. The tapes 24 also pass overa rear transversely extending idler roller 33 and around tape tightening roller 34 journalled on arms 35 carrying weights 36. The arms 35 are loosely mounted on a fixed transversely extending stay shaft 37.

The sheet S1 fed by the lower level feeder 15 onto the tapes 24 is advanced by said tapes over a transversely extending slotted die plate 38 and a transversely extending bridge-plate 39 and onto conveyor tapes 40 which continue the advance of said sheet until its leading edge engages novel timed front registering means which temporarily arrests the movement of the sheet and holds it in position for the action of timed slitting mechanism hereinafter described and which acts to slit the sheet S1 transversely at spaced points along a line where a first transverse fold is to be subsequently made in said sheet centrally between the front and rear edges thereof. As shown in Figs. 1 and 2, the die plate 38 is provided along the entire length thereof with a plurality of closely spaced slots 41 extending transversely of the direction of travel of the sheet S1 over said plate, and the latter is made into two parts to facilitate the manufacture thereof and the forming of the slots 41 therein. The die plate 38 is bolted or otherwise suitably secured to a cross bar 42 which is bolted or otherwise suitably secured at opposite ends thereof to side frame members 43 of the conveyor. The bridge plate 39 is suitably supported by the side frame members 43 which also serve to suitably support the bridge plate 22, the rock shaft 26, the tape rollers 31, 32 and 33, and the stay shaft 37 previously described.

The tapes 40 are suitably driven at the same surface speed as that of the tapes 24 and for this purpose the rear portions of the tapes 40 pass around a transversely extending driven roller 44 which is journalled in suitable bearings on the side frame members 43. The tapes 40 extend forwardly from the roller 44 to a point directly beneath the front or discharge end of the feed board 20 of the upper level feeder 16 (Fig. la), and then they pass around a transversely extending idler roller 45 also journalled in suitable bearings on the side frame members 43. The tapes 40 also pass over a rearwardly disposed transversely extending idler roller 46 and around tape tightening rollers 47 (Fig. l). The idler roller 46 is journalled in suitable bearings in the side frame members 43,

and the tape tightening rollers 47 are journalled on arms 48 that carry weights 49. The arms 49 are loosely mounted on a transversely extending stay shaft 50 which is suitably secured to the side frame members 43.

As stated above, the sheet S1 is advanced by the tapes 24, 40 until the leading edge thereof engages novel front registering means which temporarily stop said sheet and hold it in proper position for the action thereon of a timed slitting mechanism. This front registering means comprises two or more transversely aligned sheet stops 0r gage fingers 51 (Figs. 1 and 3) secured to arms 52 Which, in turn, are adjustably secured to a transversely extending rock shaft 53 disposed beneath the upper reaches of the tapes 40. The stops or fingers 51 are thus arranged for pivotal movement by shaft 53 into and out of the path of movement of the sheet S1 on the tapes 40, and said stops or fingers are preferably, but not necessarily, bifurcated to receive the upper reaches of certain of said tapes and to have portions thereof disposed at opposite sides of said tapes when in operative position as shown in Figs. 1 and 3.

The rock shaft 53 is journalled at opposite ends thereof in suitable bearings provided in blocks 54 (Figs. 1 and 3) which are mounted on and have screw threaded engagement with screw shafts 55 whereby said blocks and the shaft 53 may be adjusted in a longitudinal direction to locate the stopsor fingers 51 in proper position along the tapes 40 in accordance with the size of the sheet S1 and to insure that regardless of its size the sheet will be stopped in proper position for action thereon of the sheet slitting mechanism to be hereinafter described. The blocks 54 are supported and guided for straight-line longitudinal adjustment by upper and lower rail bars 56 and 57, respectively, which are boltedor otherwise suitably ssecured =toithevconveyor side frame members'43w ThescrewxshaftsSSareijoure nalled in andheld against displacement relative to brackets 58 (Fig. 1a) which are bolted orotherwise suitably secured to a cross bar 59 suitablysecured to the side frame members 43. The shafts have fixed thereon spiral gears 60 which mesh with spiral gears 61 that are fixedon a shaft 62 which extends. transversely of the conveyor tapes 40 and is journalled. in suitable bearings in the brackets 58. through a suitable opening in the adjacent side frame member 43 and has fixed thereon a handle 63 for rotating said shaft and the shafts 55to adjustthe sheet stops or gage fingers 51 longitudinally of the tapes 40.

The sheet stops or gage fingers 51 are raised and lowered into and out of the path of movement of the sheet S1 on the tapes 24, 40 at predetermined intervals in timed relation with :the feeding of saidsheet by the lower level 15, and this is effected by a cam 64 (Fig. l)- fixed on a cam shaft 65 which extends transversely of the conveyor and it suitably driven to make one complete revolution for each cycle of operation of the machine. The carn shaft 65 is journalled in suitable bearings in the conveyor side frame members 43. The cam 64 engages a roller 66 journalled on an opened cam strap 67 which straddles the shaft 65. Suitable spring means (not shown) connected with the cam strap 67 is provided for holding the roller 66 in engagement with the cam 64. The cam strap 67 is pivotally connected to a downwardly projecting .arm 68 of a bell-crank lever 69 the other arm of which projects forwardly and is indicated at 79 (Figs. 1 and 3). The bell-crank lever 69 is pivotally mounted on a shaft 71 which extends transversely of the conveyor tapes 40 and is fixed at opposite ends thereof in the lower rail bars 57. Disposed forwardly of the bell-crank lever 69 is a second similar bell-crank lever 72 having a forwardly extending arm 73Jand a downwardly extending arm 74. This bellcrank lever 72 is pivotally mounted on the adjacent lower rail bar 57. Disposed between. the bell-crank levers 69 and 72 and pivotally connected to the free ends of the forwardly projecting parallel arms and 73, respectively, of said levers, is a sheet stop or gage fingeroperating bar 75 having engaged therewith a roller 76 which is journalled on an arm 77 fixed on the rock shaft 53. The roller 76 is maintained in engagement with the bar 75 by a spring-pressed rod 78 (Fig. 3) one end of Which is pivotally connected to an arm 79 fixed.

on the rock shaft 53, and the opposite end of which is guided in a suitable manner on one of the bearingblocks 54. The bell-crank levers 69 and 72 are connected together by a link 80 which is pivotally connected to the free ends of the downwardly projecting parallel arms 68 and 74, respectively, of said levers.

It will thus appear that the shaft 53, through engagement of the parallel bar 75 with the roller 76 on arm 7'7, is cam operated in one direction by the cam 64 to raise the sheet stops or gage fingers 51 into the path of the sheets S1 on the tapes 40, and is spring operated in tlie opposite direction by the spring-pressed rod 78 through continued rotation of said cam and lowering of said bar to lower said sheet stops or gage fingers out of said sheet path. It will also appear that by virtue of the parallel bar 75 and the described arrangement of the spring-pressed rod '78, the described raising and lowering movements of the stops or fingers 51 will be imparted thereto in all positions of adjustment thereof longitudinally of the conveyor tapes 40.

Assuming now that the sheetrstops or gage fingers. 51 have been properly adjusted longitudinally of the tapes 40 for a given size of sheet S1, and that they havetbeen swungupwardly by the described means/for this .purpose to the position shown in Figs.. 1 and 3, the sheet Slis advanced by'the tapes 24'and 40 until'itsdeading" One end of the shaft 62 projects edge engagestsaid stops orfingers 'and sis :temporarilyr arrested thereby. While thetsheet-Sh is :so: arrested I-"by: the stops or gage fingers 51 said sheet, in -taccordame with the present invention, has formed therein. a plu-u rality of slits 81, as indicated in Figt .10, oftsubstantial longitudinal extent spaced along and-extending lengthwise of a transversenline-where subsequently latfirstr transverse fold is made in the sheet centrally between the front and .rearnedges thereofr The slits 81:alte'rnate with relatively narrow-tunslit portions .82 ef theusheet.

which are considerably less thanone-half thelength of t the slits, whereby-the front and rear 1halves:of thersheet will be connected together only by the-narrow unslit portions 82 and separated :from each otherforthe re inner layers or portions of the outside slit sheetSl connected at the first fold A are permitted to creep and adjust themselves at the first fold to-thechangein their relation effected by the right anglefold (3.. Thus, when the right angle fold is made. in ithecombined sheets S1 and S2 which necessitates wrapping of the :outerwlayer or portion of theslit outside sheet S1 around the innerx layers or portions of the combined sheets, crowdingior bunching of said inner layers tor portions atthe corrier of the right angle fold intersecting thefirst fold is com-- pletelyavoided and, hence, wrinkling of said=inner layersor portions at and alongsthe first fold? is completely elim-':

inatedh As shown in Figs. 1 .and-2, therslitsi 81 :are

formed inthe sheet S1 by mechanism operated and com-*1 prised. by the following instrumentalities;

Fixed on and driven by;the cam shaft 65.'-is a camv83 (Fig. l) which engages a roller 84journalled-on.a closedrz camstrap SSthat straddles saidshaft. .Adjustablycar ried by the cam strap 85*isa connecting ,rod .86 which"? is pivotally connected to an arm-'87? (Figs. l xand-'2)'fixed on a transversely extendingrockvshaft 88'-=:journalled:ini: suitablebearings in. the conveyor'side frame members? 43. Fixed on the rock shaft 88' adjacent opposite ends thereof and disposed inwardly of the. side frarne"mem-:

bers 43 are. forwardly projecting arms r 89 having 'jour-.

nalled thereon rollers 90 which project into suitable open -w ings formed in vertically extending plates 91. These."

plates 91 are spaced inwardly from and bolted or other wise suitablysecured to vertically extending: slide" bars 92which areslidably'mounted in guides .93 and between antifriction. bearings .94 journalled on eccentricipins .95. adjustably secured in said guides; The guides1-93'are bolted or otherwise. suitably. secured to the conveyor side frame members 43. One of the.-arms'89 is formed with a downwardly projectingarm 96 to. which is piv-' otally connected oneend of a spring-pressed. rod97, the r Opposite end of which is-suitably-guided on the adjacent sideframe member 43. a It will thus appearzthatthe I rock shaft 88-,thr0ugh the described op'erating'connections therefor with the cam 83 and the rod '97; is cam operated in one direction andspringoperated in-the=opposite direction to impart vertical and timedwreciprocat ing motion .to theslide bars 92 through the' described operating connections therefor with said "shaft, the cam 83 operating tolower said slide barsxandi the spring-- pressed rod 97 operating .to raise said slide bars:

The slidebars 92- projectabove the conveyor side frame members 43 and; havewbolted orotherwise suitably secured thereto. brackets :98 'whichproject inwardly therer." fromm Bolted orotherwisesuitably 'securedt0 the brackets 1981s a slitter head '99 which' extends' transversely of thezconveyors 24 and 40. above the die plate 38. Secured in a suitable manner in the underside of the head 99 and extending therealong in alignment with the slots 41 in the die plate 38 are slitter blades 100 each of which is constructed to form two relatively long slits 81 in the sheet S1 separated by relatively short unslit portions 82 of said sheet. Slidably mounted on the slitter head 99 at opposite sides thereof are transversely extending spring controlled's'heet clamps 101, said clamps being broken away inFig. 2 for the purpose of clearly illustrating the slitter blades 100.

When the sheet S1 has been advanced by the tapes 24, 40 across the die plate 38 into engagement with the raised sheet stops or gage fingers 51, the head 99 descends and the blades 100 enter the slots 41 in the die plate 38, thus piercing the sheet S1 and forming therein transversely thereof a plurality of relatively long slits 81 on and along a transverse line where the first fold A is to be made therein, as hereinafter described, said blades leaving relatively narrow unslit sheet portions 82 between said slits. In a commercial embodiment of the invention, the slits 81 formed by the blades 100 are approximately five-eighths to three-quarters of an inch in length, and the unslit sheet portions are approximately one-eighth of an inch in length.- These relative lengths of the slits 81 and the unslit sheet portions 82 may be varied depending upon the thickness and quality of the book or magazine stock acted upon, and upon folding conditions, but atall times the length of the unslit sheet portions 82 should be considerably less than one-half the length of the slits 81. By simply adjusting the connecting rod 86 relative to the cam strap to increase or decrease the length of the rod, the extent that the blades pierce the sheet and, hence, the length of the slits 81 may be varied to the proper degree.

Upon descent of the slitter head 99, the clamps 101 engage the sheet S1 and clamp it against the die plate 38 to insure against displacement of the sheet during the slitting operation. When the head 99 rises, the clamps 101 first continue to bear on the slit sheet S1 and strip it from the blades 100 whereupon said clamps rise with the head 99 so that the next sheet S1 to be slit may pass under said clamps and the blades 100 into position for action thereof on said sheet. In order to insure passing of the sheet S1 under the clamps 101, guide fingers 102 (Fig. 1) are'provided for directing the leading edge of said sheet beneath said clamps. These guide fingers 102 are suitably secured to a transversely extending bar or tube 103 which is suitably anchored to the conveyor side frame members 43.

After the slits 81 have been formed in the sheet S1 transversely thereof, and the slitter head 99 has been raised to its extreme or gage fingers 51 are lowered whereupon the slit sheet S1is further advanced by the tapes 40 assisted by timed drop rollers 104 (Figs. 1 and 4) into the folding machine hereinafter described and wherein said sheet is folded together with a second sheet at least three times to produce a thirty-two page closed head signature that is free of wrinkles on the inner pages thereof. The drop rollers 104 are journalled on arms 105 fixed on a transversely extending rock shaft 106 which is journalled in suitable bearings in the conveyor side frame members 43. The drop rollers 104 are raised and lowered at predetermined intervals in timed relation with the operation of the slitter mechanism, and for this purby the cam shaft 65. This cam 107 has engaged therewith a roller 108 journalled on a closed cam strap 109 which straddles the shaft 65 and is pivotally connected to a downwardly projecting arm 110' that is fixed on the rock shaft 106. The roller 108 is maintained in engagement with cam 107 by aspring-pressed rod lll'one end of which is pivotally connected tothe arm 110 and the opposite.

uppermost position, the sheet stops or :gage fingers 132 8 end of which is guided in any suitable manner on the adjacent conveyor side frame member 43.

From the conveyor tapes 40 the unfolded and slit sheet S1 passes over a bridge-plate 112 (Fig. 1a) suitably supported on the conveyor side frame members 43, and onto the in-feed conveyor tapes 113 of a folding machine which, in the illustrated embodiment, is of the well known Quad type, but may be any one of many well known types of signature folding machines as hereinbefore pointed out. The Quad type of folding machine herein illustrated, beginning with the in-feed conveyor 113 and ending with the packer-box deliveries is, except as here inafter pointed out, identical in construction and operation as the folding machine disclosed in the United States Patent No. 2,232,152 hereinbefore referred to. Accordingly, only those portions of said folding machine with which in illustrated and will be hereinafter briefly described, and for a more complete description of the construction of said folding machine reference may be had to the above mentioned patent.

The tapes 113 pass around a rear transversely extending driven roller 114 and around a front transversely extending idler roller 115 (Fig. 1a). The tapes 113v also pass over a transversely extending idler roller 116 and around tape tightening rollers 117 journalled on arms 118 carrying weights 119. The arms 118 are loosely mounted on a fixed transversely extending stay shaft 120. The unfolded and slit sheet S1 is advanced by the tapes 113 in a horizontal plane over transversely extending movable and fixed folding bars 121 and 122, respectively, and onto conveyor tapes 123 which are driven at the same surface speed as that of the tapes 113 and carry the sheet S1 into proper longitudinal position for folding thereof. As the sheet S1 is advanced by the tapes 113 the bar 121 is moved toward the bar 122 to close the space therebetween and enable said sheet to pass thereover without interference. After the sheet S1 has passed over the bars 121, 122 and moved into proper position for folding, bar 121 is moved away from bar 122. These movements of bar 121 are effected by suitable mechanism including a transversely extending rock shaft 124 having fixed thereon spaced arms 125 to which are pivotally connected links 126 which, in turn, are pivotally connected to said bar.

The tapes 123 pass around a rear transversely extending driven roller 127 (Fig. 1a) which has been relocated to provide a space between the same and the folding bar 122 for the reception and operation of novel side registering means to be hereinafter described. The front portions of the tapes 123 pass around idler rollers 128 journalled on arms 129 adjustably clamped on a fixed cross bar 130 to maintain proper tension on the tapes 123. Guide fingers 131 removably mounted in a suitable manner on the framework of the tape conveyor 123 are provided for directing the sheet S1 from the folding bar 122 onto said conveyor.

The unfolded and slit sheet S1 is carried forwardly by the tapes 123 until its leading edge engages sheet stops or gage fingers 132 (Fig. la) which arrest the movement of said sheet and hold it in position for the making of the first transverse fold therein as hereinafter described. The stops or fingers 132 extend in alignment transversely of the tapes 123 between the latter and project below the upper reaches of said tapes. The stops or fingers 132 are adjustably mounted on a transversely extending bar 133 mounted on and having screw threaded engagement with screw shafts 134. The shafts 134 are journalled in and held against displacement relative to brackets 135 bolted on a fixed cross bar 136. The shafts 134 have fixed thereon spiral gears 137 which mesh with spiral gears 138 that are fixed on a transversely extending shaft 139 journalled in suitable bearings in the brackets 135. The shaft 139 has also fixed thereon a handle 140 for rotating said shaft and the shafts 134 to adjust the sheet stops longitudinally of the tapes 123 in the present invention is actually concerned is here:

accordance with the size-of the sheet S1-andsto insure thatsaidsheet will be stoppedby said stops or fingersin proper: position for making the first or transverse fold therein on the line of the slits 81 as hereinafter described.

Before proceeding with the description of the various folding mechanisms of the folding machine, .the mechanism which,in accordance with the present invention, is incorporated in said machine for feeding and associating a second unfolded sheet S2 with thefirst unfolded and slit sheet Sl will now be described. As the first unfolded and slit sheet S1 advanced by the conveyortapes 4t) approaches the front end of said conveyor, a second unfolded sheet S2'is fed by the upper level feeder 16 therefrom so that both sheets will travel simultaneously into the folding machine in spaced superposed relation and arrive approximately at the same time in proper folding position.

The second unfolded sheetSTfedby the upper level feedef 16 in timed'relation with the feeding of the first unfolded sheet S1 by the lower level feeder 15,'passes into the folding machine over a bridge plate 141 (Fig. 1a) suitably supported on the framework of the feeder 16, and onto a down-hill conveyor comprisinga plurality of trans versely'ispaced endless tapes 142 which are inclined upwardly and forwardly from the horizontal and are arranged in superposed relation with the'lower level tapes 113. Thetape conveyor'142 is substantially of the same length as that of the tape'conveyor 113 and is driven at the same surface speed as that of the tape conveyor 113. The rear portions of the tapes 142 pass around a driven roller 143 which extends transversely of the folding machine'and is disposed in vertical alignment with the lower tape roller 114. The front portions of the tapes 142 pass around a transversely extending idler roller 144 which. is disposed directly above the lower tape roller 115 and is spaced therefrom a distance sufficient to permit the sheet S1 on the lower tape conveyor tape 113 to pass beneath the same'without interference. The tapes 142 also pass over and under tape tightening rollers 145 which are journalled in pairs on arms 146 at opposite .ends thereof. The arms 146 are mounted for pivotal adjustment on other arms 147 which are bolted or otherwise suitably secured to a fixed cross bar 148; The rollers 143 and 144 are journalled in suitable bearings on the side frames" of the folding machine, and the cross bar 148 .is'secured in any suitable manner on said side-frames which have been suitably extended from that shown in. the above mentioned United States Patent No. 2,232,152 to receive said rollers and said bar and other elements'hereinafterl described and forming part of the second-sheet mechanism.

Cooperating with the tapes 142 to feed thesecond sheet Sz-therealong are timed drop rollers 149' (Fig.11a)

which are journalled on arms 150 fixed on a rock shaft 151 extending transversely ofthe folding machine and journalled in suitable bearings on the side'frames thereof. The drop rollers 149 are raised and'lowered at predeter-' mined intervals in timed relation with the feeding of the sheet S2 bythe upper lever feeder 16 and this is accorn= plished by the following iustrumentalities. Fixed on the driven single revolution cam shaft 152 of the folding" machine is a cam 153 having engaged' therewitha roller 154 that isjournalled on an arm 155' fixed on therock shaft 151'. The roller 154 is maintained in engagement with the earn 153 by a spring-pressed rod 156 one end of which is pivotally connected to the arm 155' and-the opposite endof which is guidedin a suitable manner on one of thefolder side frames. The arm 155 is thus cam operated in one direction and spring operated in the opposite directionwhich causes rocking of the shaft 151 the sheet S2 is fed. onto the tapes 142, the drop rollers 149' are in raised position eifected by the cam 153 Whereupon they are immediately lowered by the springepressed' rod 156" to assist saidtapes in advancing the'sheet down and raising and lowering of the drop rollers.149. When wardly. and forwardly to other conveying-means to he presently described...

While the first unfolded and slit sheet. Slis beingfed by the tapes 113 forwardly overthe bars 121, 122 onto. the tapes 123, the second unfolded sheet S2 'isbeing fed by the tapes 142 downwardlyyandforwardly over other folding bars 157 and 158 and onto an .uphill conveyor comprising a plurality' of transversely spaced endless" tapes 159'whi'ch are inclined upwardly and rearwardly from the horizontal and'are arranged in superposed rela-- tion with the lower level tapes 123. The bars-157, 158 Y extend transversely of the machineabove the bars 121 and 122, respectively, and are'vertically spaced from the latter bars to enable the firstunfolded and slit sheet S1 to pass over and beyond the bars1121, 122. The upper and lower surfaces ofthe bars 121 and 157, respectively, are preferably tapered to provide a wide entrancethroat for the passage of the sheet Slbetween said bars without interference The bar 158 is immovably fixedirra suit-' able manner to the fixed bar 122, and the bar-157 is secured in a suitable mannerxto the'imovablebar 121. for movement therewith toward the bar 158Jby' the described means for this purpose tosclose the space between the bars 157, 158' and enable the second sheet S2 to pass thereover without interference. Suitable curved guide tongues or fingers 160:are provided at the front end of the tape conveyor 142 for directing the sheet S2 from the inclined tapes forwardly over thefolding bars 15'7,158,-'said tongues being disposed between:

the tapes and extending: overxthe barv 157 and suitably mounted on the framework of said conveyor."-

The tapes 159 are'driven at the 'same'surface speed; as: that of the tapes 142 andzfor' this purpose thetap'es 159" pass around a transversely extending ,driven roller 161.

and transverselyextending idler rollers 162 and 1163;-

The tapes 159 also .pass aroundntape tightening rollers 164 journalled on arms 165 which are adjustably clamped to a cross 'bar 166. The tape rollers"161, .162 and 163 are journalled in suitable hearings in the side framesof: the folding machine, and=the cross bar 166 is .secured' in any suitable manneron said. sideframes. The idler roller 163 is arranged to provide a spacebetween the-1 same and the folding-bar 158 for: the reception and opera the upper surface of said bar.

The second sheet S2 is carried forwardly and upwardly'z' by the tapes 159 until itsleading'edge engages sheet *stops'iw or gage-fingers 168 whiclr-arrest the movement of:saidw sheet and hold it in position for the making of the first transverse fold therein simultaneously with theslit' sheet f S1. 1 The stopsor fingers168 extendin alignment trans versely of the tapes-159' between thelatter andproject below the upper reaches of 'saidtapes. The stops or fingers 168 are adjustablymounted on a transversely extending bar 169 mountedonandhavingscrew threaded engagement with screw shafts' 170. Th'e shafts 170are1: journalled in and held against displacement relative to brackets '171bolted on a fixed =crossbar172 carried bythe folder side frames; The shafts'170have-fixed thereonspiral gears 173which"mesh='with spiral gears 174 that are fixed ona transversely extending shaft 175 journalled in suitable bearings in the brackets 171. The shaft 175 has also fixed thereona handle 176 for rotating said shaft and the shafts 170 to adjust the sheet stops or gage fingers 168-longitudinally of the tapes 159 'in accordance with the size of the sheet 'S2 'and to insure that said sheet will be' stoppedby said' stopsor- =fingersin proper position so that the printing thereoniis in accurate longitudinal 1 I register with the printing on the underlying slit sheet S1.

Assuming that the stops or gage fingers 132 have been properly adjusted for the making of the first or transverse fold A on the line of the slits 81 in a given size of sheet S1, and that the stops or gage fingers 168 have also been properly adjusted for the making of said fold simultaneously in the same size of sheet S2 with the printing thereon in accurate longitudinal register with the printing on the underlying sheet S1, the leading edges of the sheets S1 and S2 fed forwardly by the tapes 123 and 159, respectively, engage the Stops or gage fingers 132 and 168, respectively, at approximately the same time and said sheets are thereby arrested and held in proper position for the making of the first fold A simultaneously therein.

At this time the underlying slit sheet S1 and the overlying unslit sheet S2 are, in accordance with the present invention, moved laterally on their respective conveyors 113, 123 and 142, 159 simultaneously and independently of each other to side register the same with respect to each other so that the printing on one sheet is in accurate lateral register with the printing on the other sheet. This side registering operation on both sheets S1 and S2 is accomplished through the medium of novel side registering mechanism, indicated generally at 177 (Fig. 1a), disposed in the space between the folding bars 122, 153 and the tape conveyors 123, 159, and preferably operated and comprised by the following instrumentalities.

Fixed on and driven by the cam shaft 152 is a cam 178 (Fig. la) which engages a roller 179 journalled on and at one end of a lever 180 which is pivotally mounted intermediate its ends at 181 on the adjacent side frame of the machine. The roller 170 is maintained in engagement with the cam 178 by suitable resilient means, such as an extension coil spring 182 having one end thereof connected to said lever adjacent said roller and the opposite end anchored in any suitable manner on the adjacent side frame of the machine. It will thus appear that the lever 180 is cam operated in one direction and spring operated in the opposite direction and thereby imparts vertical motion to an adjustable rod 183 (Figs. la and having its lower end pivotally connected to the opposite end of said lever.

The upper end of the rod 183 is pivotally connected to an arm 184 of a bell-crank lever 185 the other arm of which is indicated at 186 (Fig. 5). The bell-crank lever 185 is pivotally mounted on a block 187 bolted or otherwise suitably secured to one end of a cross bar 188 which is secured in any suitable manner to the side frames of the machine. Pivotally connected to the arm 186 of the bell-crank lever 185 is one end of a link 189 (Figs. 5 and 6) the opposite end of which is pivotally connected to one end of a shaft 190 which extends transversely of the machine and is slidably mounted in suitable bearings provided in spaced brackets 191 bolted or otherwise suitably secured to the cross-bar 188. The shaft 190, through the described connections therefor with the lever 180, will thus be continuously reciprocated transversely of the folding machine in timed relation with the feeding of the sheets S1 and S2 simultaneously into said machine.

Releasably clamped to the shaft 190 for adjustment therealong and reciprocated by said shaft is a bracket 192 (Figs. 5, 6 and 7) which projects downwardly from said shaft and has secured thereto or formed integrally therewith adjacent the lower end thereof two lower gripper jaws 193 and 194. The gripper jaw 193 extends from the bracket 192 transversely of the tape conveyors 113, 123 and is so located that the upper surface thereof is substantially in the same plane as that of the upper reaches of the tapes 113 and 123. The gripper jaw 194 extends from the bracket 192 transversely of the tape conveyors 142, 159 and is so located that the upper surface thereof is substantially in the same plane as that of the upper surfaces of the folding bars 157, 158, said gripper jaw 194 being also offset rearwardly from the gripper jaw 193for a purpose to appear hereafter.

Secured in any suitable manner to the bracket 192 adjacent the lower end thereof is a stud 195 (Figs. 5 and 6) having pivotally mounted thereon in coaxial abutting relation two upper gripper jaws in the form of levers 196 and 197; The upper gripper jaw-lever 196 cooperates with the fixed lower gripper jaw 193 to grip the slit sheet S1 fed therebetween by the tapes 113 and for this purpose said lever has pivotally mounted thereon for free floating movement a U-shaped sheet engaging shoe 198. The upper gripper jaw-lever 197 cooperates with the fixed lower gripper jaw 194 to grip the second sheet S2 fed therebetween by the tapes 142 and for this purpose said lever has also pivotally mounted thereon for free floating movement a U-shaped sheet engaging shoe 199.

The upper gripper jaw comprising the lever 196 and shoe 198 normally tends to close relative to the lower gripper jaw 193, said tendency being produced by a spring 200 (Fig. 5). One end of the spring 200 engages against the upper side of the lever 196 and the opposite end of said spring engages against an adjusting nut 201 threaded on the upper end of a pin 202 which passes through said spring. The pin 202 also passes through a suitable opening in the lever 196 and is secured in any suitable manner in the bracket 192. The upper gripper jaw comprising the lever 197 and shoe 199 also normally tends to close relative to thelower gn'pper jaw 194, said tendency being produced by a spring 203 surrounding a pin 204 and having one end thereof engaging against the upper side of said lever and the opposite end thereof engaging against an adjusting nut 205 threaded on the upper end of said pin. The pin 204 passes through a suitable opening in the lever 197 and is secured in any suitable manner at its lower end in the bracket 192. It will thus appear that pressure between the jaws 193, 196 produced by the spring 200, and between the jaws 194, 197 produced by the spring 203 may be varied by the adjusting nuts 201 and 205, respectively.

The gripper jaw-levers 196 and 197 are simultaneously raised and lowered relative to the jaws 193 and 194, respectively, during reciprocation of the bracket 192 and these movements are obtained in the following manner and by the following described means. Pivotally connected to an arm 206 (Fig. 5) formed integrally with the gripper jaw-lever 196 are toggle links 207 which, in turn, are pivotally connected by a knee pin 208 with toggle links 209. The toggle links 209, in turn, are pivotally connected to a lug 210 formed on the bracket 192. The gripper jaw-lever 196 is provided at one side thereof with a lug 211 which projects rearwardly therefrom beneath an adjustable abutment screw 212 threaded in a lug 213 formed on the gripper jaw-lever 197 at one side thereof and overlapping the lug 211. It will thus appear that when the lever 196 is raised relative to the jaw 193, the lever 197 is simultaneously raised relative to the jaw 194 by the lever 196 through engagement of the lug 211 on the latter lever with the abutment screw 212 on the lever 197. When the lever 196 is lowered by spring 200 relative to the jaw 193, said lever moves downwardly away from the lever 197 whereupon the latter lever is simultaneously lowered by the spring 203 relative to the jaw 194.

Disposed adjacent to and outwardly of the bracket 192 is a bracket 214 (Figs. 5 and 6) formed with a rearwardly and downwardly projecting arm 215. This bracket 214 is mounted on and adjustable along the cross bar 188 to proper position relative to the reciprocating bracket 192. The cross bar 188 is provided longitudinally thereof with spaced threaded openings (not shown) and when the bracket 214 has been properly adjusted relative to the reciprocating bracket 192, said bracket 214 is secured to the cross bar 188 by a bolt 216 which is inserted in a slot 217 in the bracket 214 and is threaded into the proper one of said threaded .openings. The slot 217 in bracket 214 provides for adjustment of said bracket within limits along the cross bar 188 without having to remove' the bolt in the arm 215 of bracket 214'is a toggle breaking pin 219 which'projects inwardly and downwardly from said bracket into the path of inward movement of thetoggle knee pin 208, the latter] pin'being'rearwardly extended for engagement with the pin 219.

Disposedadjacent-*toand inwardly of the reciprocating'bracket 192" is a bracket 220*( Figs.'5 and'6) formed with a rearwardlyj and" downwardly projecting arm 221; This bracket 2201s mountedon-and adjustable along the cross bai' 188'to proper position relative to the reciprocating b'racket 1925 The cross bar 188is further provided longitudinallythereof with spaced threaded openings (not shown) and when the bracket-220 has been properly adjusted "relative to the reciprocating bracket 192, said bracket 220 is secured to'thecrossbar188by a bolt 222 which is inserted in a slot 223 in the bracket 220" and 'is threaded intothe proper one of said threaded openings. The slot 223 in bracket 220 provides forladjustment of said bracket within limits along the bar 188 without havingto remove the bolt 222 from'the bracket and said bar.

Passing loosely through suitable 221 of bracket 220 are'two adjusting screws'224 and 225 having fixed thereon at thefouter ends thereof two side registering plates 226"and227, respectively, arranged in face to'face relation. The plate 226 projects slightly below the upper sur ace of the fixed lower gripper jaw 193, andthe plate 227 projects slightly below the upper surface of the fixed lower gripper jaw194. The plate 226 has secured thereto inany suitable manner at th'elower end thereof a side registering'block 228 which projects inwardly therefromtoward and' below the side registering plate 227. The thickness of the block 228'exceeds the minimum distance between the plates 226;, 227*plus the thickness of the plate 227, whereby the sheets S1 and S2 openings in the arm may be accurately side registered'wiflr respect to each other under all norinal conditions. The plates 226, 227 and the block228have aligned openings therein through which the grippei'jaws 193,194,196 and 197 are reciprocated. Threaded "on-the adjusting screws224, 225 at opposite'sidesof the arm 221*areadjusting and locking nuts 229 by means of which theside "registering'plates 226, 227' may be adjustedlater'ally to, 7 side "registering positions. The plates 226, r 227 have secured theretoinany suitable manner guide pins 230"which are slidably engaged in suitable openings in the arm 221 and prevent tilting'movement of said platesrelative to said arm. The bracket 192is guided for straight line reciprocating movement and heldagainst" rotation relative to shaft-190"bya roller 231(Fig.;7) which is journalled on said bracketand -is engaged in a groove 232 formed 1 by the cross"bar188 anda shortened-bar 233'bo1ted'or otherwise suitably securedto said cross bar. I

Assuming now that the reciprocating bracket 192 -is moving inwardly with the gripper jaws 196and 197 open, and'thatthe slit sheet 81 has beenfedby the tapes 113, 123 between the gripper'jaws 193, 196 intoengageinent with th'e'stops or gage fingers 132; and that the second sheet S2 has been fed by the"'tapes-142, 159 between the gripper jaws 194, "197 into engagement with the stops or gage fingers 168. The sheets 81 registered wit-h'respect to" each'other by 'thestops or fingers 132 andl68j'respectively, andare properly positioned for the making of thefirst-transverse' fold A simultaneously therein. Thereupong the front registered sheetsSl, S2, being atrest against the stops or fingers 132 and 168, respectively; are simultaneously gripped 'by S1, SZby'the *jaws193; 196-and 194, 197, respectively,

and locked in, proper and- S2" are thus front the jaws 193, r 196 and 194, 197, respectively: This gripping of the sheets res'ults from the toggle knee pin- 208 striking the toggle. occurs as the bracket 192 inoves upon breaking of the toggle 207, 208by the pin 219, thejaws gage the block 228 and plate 227, respectively. The'sheets 1 S1, S2 are thus independently side registered with respect to each other, at which time'the jaws 193, 196 and 194,

197 begin to slide off said sheets through continued out- Ward movement thereof with thebracket 192. The toggle 207, 209 then strikes the toggle straightening'pin 218,

thereby straightening said toggle and raising jaw 196 relative'to the jaw 193 against jaw 196 relativetothe jaw 194 against the tension of the spring 203. The-jaws 193,196 and 194, 197 are thus opened simultaneously whereupon they move inwardly with the bracket 192 to engage the next two front regis tered sheets 'duringthe next cycle of operation of the machine and move said sheets sidewise from rest to side register thesame,'as previously described.

After the sheetsSl and S2 have been front and side registered, as previously described, the overlying sheet S2 is tuckedbetween the folding bars 157, 158 into engagement with the underlying sheet S1 and then both said sheets are simultaneously tucked between the folding bars 121,--122 anda pair of driven folding rollers 234 (Fig. la) by a timed folding knife 235, whereupon a first transverse fold -A (Fig. 10) is made in the combined sheets S1, S2 on the line of the slits 81 andthe once folded second sheet-S2 is disposed-within the once folded and slitfirst sheetSlg resulting in fourhalf sheets or eight pages. The rollers234 extend transversely of the machine below the folding bars 121,- 122 and are driven continuously in a The knife 235 extends transversely of suitable manner. the machine above the plane of the folding bars 157, 158 and is secured at opposite ends thereof to guided slides 236. The slides 236 are reciprocated vertically to raise and lower the knife 235 at proper intervals by suitable mechanism including two arms 237 fixed on opposite ends of a rock shaft 238'andhaving pivotally connected therewith 'the lower ends of adjustable links 239 the upper ends of which are pivotally connected to said slides. The adjustable links 239 enable raising of the slides 236 to posi-' tion'the' knife 235 above the planeof the folding bars 157, 158 for folding of the second sheet S2 simultaneously with the first sheet S1; as previously described.

The combined once folded sheets S1 and S2 are delivered by the rollers 234 between a transversely extending tape roller 240 (Fig. la) and conveyor tapes 241 passing under said "roller. a transversely extending'driven tape roller 242, around a transversely extending'idler roller 243, over a transverse ly extending idler roller 244 and around tape'tightening rollers 245. The tape tightening rollers 245 are journalled on arms 246 that carry weights 247, said arms being loosely mounted on a transversely extending stay shaft 248.

The combined oncefolded sheets S1, S2 are carried forwardlyby the tapes 241 over a transversely extending slotted die plate 249, a transversely extending slotted fold plate 250 and'longitudinally extending laterally spaced sheet supporting bars 251 until the leading and folded edge A thereof engages transversely aligned stops or gage fingers 252 which are reciprocated to occupy first a rearward position and then a forward position. The stops or fingers 252 in their rearward position operate to arrest the movement-of the combined once folded sheets S1, S2

j the tension of spring 200" whereupon the jaw 197 is simultaneously raised by the The tapes 241 also pass around timed slitting mechanism, indicated generally at 253. This slitting mechanism 253 and the die plate 249 are the same in construction as that of the die plate 38 and the slitting mechanism comprising the head 99, the blades 100 and the sheet clamps 101 hereinbefore described and illustrated in Figs. 1 and 2 of the drawings, therefore needing no detailed description herein, except to say that the die plate 249 is suitably secured to a fixed cross bar 254, and that the slitting mechanism 253 is operated at proper intervals by suitable means including two arms 255 fixed on opposite ends of a rock shaft 256 and having pivotally connected therewith adjustable rods 257 which are pivotally connected to guided slides (not shown) that support and impart vertical motion to the blade carrying head of said mechanism.

When the combined once folded sheets S1, S2 have been advanced by the tapes 241 across the die plate 249 and bars 251 into engagement with the rearwardly positioned stops or gage fingers 252, the slitting mechanism 253 descends and forms in and through the four halves of said sheets a plurality of relatively long slits 258 (Fig. spaced along and extending lengthwise of a transverse line where a second transverse fold B (Fig. 10) is to bemade in the combined once folded sheets parallel to the first transverse fold A by a folding knife hereinafter described and which is raised at the time the slitting operation takes place. The slits 258 and the relatively short sheet portions 259 (Fig. 10) separating said slits are of the same longitudinal extent as that of the slits 81 and sheet portions 82 hereinbefore described, whereby the four halves of the combined once folded sheets S1, S2 are considerably weakened on the line of the second fold B so that when a third fold C is subsequently made in the combined sheets following the second fold B and at right angles thereto, the outer and inner layers of the combined twice folded sheets are permitted to creep and adjust themselves to the change in their relation effected by the right angle fold C, thus wrinkling of the innermost layers at the corner of the right angle fold intersecting the second fold B and along the latter fold is also completely avoided.

The stops or gage fingers 252 project downwardly between the bars 251 and are releasably clamped to a transversely extending bar 260 (Fig. 1a) suitably secured to brackets 261 which are mounted on and have screw threaded engagement with screw shafts 262. The shafts 262 are slidably mounted in bearing brackets 263 which are suitably secured to a tie member 264 at the front and rear thereof. The shafts 262 have fixed thereon hand wheels 265 for turning said shafts and thereby adjust the position of the stops or gage fingers 252. The shafts 262 are also slidably keyed to spiral gears 266 which mesh with similar gears 267 fixed on a transversely extending shaft 268 journalled in suitable bearings in the front brackets 263, whereby turning motion imparted to one of said shafts by its hand wheel 265 will be imparted to the other of said shafts. Reciprocating motion is imparted to shafts 262 and the stops or gage fingers 252 at proper intervals by suitable mechanism including two arms 269 which are fixed on a transversely extending rock shaft 270 and are pivotally connected as at 271 to said shafts.

After the slits 258 have been formed in the combined once folded sheets S1, S2 by the slitting mechanism 253 and the latter has been raised to its inoperative position, the combined once folded sheets S1, S2 are gripped inwardly of the folded edge A by jaw grippers 272 (Fig. la), whereupon the stops .or gage fingers 252 and said grippers are moved to a definite forward position, the grippers carrying the combined sheets along with the stops or fingers until the line of slits 258 in the four halves of said sheets are disposed immediately over the transversely extending slot in the fold plate 250. At this time the grippers 272 are opened and the combined once folded sheets S1, S2 are collectively side registered by suitable means for this purpose (not shown). The grippers 272 are mounted on the gage bar 260 in transverse alignment with the gage stops or fingers 252, and said grippers are opened and closed at proper intervals by suitable means for this purpose (not shown). In the rearmost position of the stops or gage fingers 252 the grippers 272 are open to enable the leading folded edge of the combined once folded sheets S1, S2 to pass between the jaws of said grippers into engagement with said stops or fingers.

Assuming now that the combined once folded sheets S1, S2 have been drawn forwardly by the grippers 272 so that the line of slits 258 across said sheets is centrally aligned with the slot in the fold plate 250, and that the combined sheets have been collectively side registered, as above described. Thereupon a transversely extending folding knife 273 descends and forces the combined once folded sheets S1, S2 through the slot in the fold plate 250 and into the bite of a pair of folding rollers 274, thus making the second fold B in the combined sheets on the line of the slits 258 and parallel with the first fold A, resulting in eight quarter sheets or 16 pages. The knife 273 is secured at opposite ends thereof to guided slides 275 which are reciprocated vertically to raise and lower said knife at proper intervals by suitable mechanism including two arms 276 fixed on opposite ends of a transversely extending rock shaft 277 and having pivotally connected therewith the lower ends of adjustable rods 278 the upper ends of which are pivotally connected to said slides.

The combined twice folded sheets S1, 82 are fed downwardly by the folding rollers 274, with the folded edge B thereof leading, to and between pairs of feed rollers 279 (Fig. 1a) fixed on opposed transversely extending driven shafts 280. One of the shafts 280 has also fixed'thereon metal collars (not shown) which cooperate with rotary cutters 281 fixed on the other shaft 208 to divide the combined twice folded sheets S1, S2 into four separate twice folded sixteen page sections as the combined sheets are further fed downwardly by the feed rollers 279.

The combined twice folded sheets S1, S2 constituting the two outer twice folded sixteen page sections are delivered by the feed rollers 279 to conveyor tapes 282, and the combined twice folded sheets S1, S2 constituting the two inner twice folded sixteenpage sections are delivered by the feed rollers 279 to conveyor tapes 283 disposed below the plane of the tapes 282. The tape conveyors 282, 283 form part of four separate longitudinally extending laterally spaced and adjustable folding units for imparting a third and final fold C at right angles to the folds A and B simultaneously to the outer and inner twice folded sixteen page sections independently of each other,- thus producing four separate thirtytwo page signatures having closed heads and which are entirely free of wrinkles on the inner pages thereof. These folding units each includes a pair of longitudinally extending driven folding rollers 284, a cooperating longitudinally extending folding knife 285, transversely extending front stops or gages 286, and a pair of longitudinally extending driven squeeze or pressure rollers 287.

The tapes 282 of each of the two outer folding units pass around a transversely extending driven roller 288 and around a tranversely extending idler roller 289. The tapes 282' also pass under and over transversely extending driven and idler rollers 290 and 291, respectively. The tapes 283 of each of the two inner folding units pass around a transversely extending driven roller 292 and around a transversely extending idler roller 293. The tapes 283 also pass under and over transversely extending driven and idler rollers 294, 295, respectively. The front stops or gages 286 of the outer and inner folding units are secured to rods 296 and 297, respectively, which are adjustably mounted on the framework of said units. The knives 285 of the outer and :inner folding units are secured to guided slides 298 which are reciprocated; vertically injunison to, simultaneously rais said: sections engage thev front stops or gages ,236,v286.

Thereupon the outer, and inner lIWlCCTfOldBd sixteen page: sections are simultaneously side registered with respect to: the knives; ZSSI by suitable. means. for this purpose, (not shown). At this time the knives 285: are simultaneously lowered and the. inner and. outertwice folded; sixteen page, sectionslare tucked downwardly int0, thev bites of the'foldi'ng rollers. 284 which then act: to impart a third or final fold" C to the outer and inner sections at right angles to the. two parallel folds A. and B previously made therein so that each section now com prises a signature, having thirty-two pages. The. outer and inner thirty-twov page. signatures are then delivered downwardly by the folding rollers 284 between the bites of thes-squeeze rollers 287 which, in turn, deliver the outer andinner thirty-two-page signatures for. reception ire-upper and, lower packer boxes. 301 and 302, respec-. tively, thus completing one cycle of operation or the. machine.

The operations performed by the machine on each set oftwo sheets S1, SZareperformed, in the order described, on each succeeding set of'two sheetsand it will thus appear that the sets of two sheets fed successively into. the machine are. each formed into thirty-two page signatures and-that series ofithesev signatures, each includ ing; four thirty-two. page signatures, are. delivered successively from the; machine; during successive cycles of operation thereof. The present invention thus enables, duringv each cycle. of operation. ofthe machine, the production. of; four signatures each having. a number of pages therein equal to two signatures folded'in like man nerwin existing machinesxofrthe character described duringsuccessive'cyclesof operation thereof. Additionally, the production of closed; headtsignatnres comprising sixteen interlocked leaves; or thirty-two. pages materially. simplifiessubsequeht: handling thereof andtre'duces the number of: operations; machines; and mechanisms. subsequently required in the production of'books, magazines, or the-like from saidsignatures. t i \Inaccordance with the present invention, a further method. of: preventing wrinkling of the inner pages of the signatures is 'provided whieh resides in forming in the'l'firstasl'ieet S1" ontheline. of the first fold" and also in andxthrough the combined once folded sheets S1, S2 on the:.line of'th'e-second-fold, a, plurality of relatively short'aclosely. spacedaslits 303, as indicated in Fig. 11, whichzextendsirr opposite directions across said fold lines and longitudinally. of the: sheets. These slits 303' have the same; effectrand advantages. as that of the relatively long transversely extending: slits 81', 258, and have a further advantage in that with said slits 303 extend longitudinally of the sheets said'sheets are maintained in one .solid:pieceand are not severed along the fold'lines for-a, substantialportion ofthe width thereof as is the case withttheslits 8 1 andi25'8; The slits 303'serve-to divide a; relatively. narrow. central transverse portion of the sheet: into aplurality ofrelatively short and narrow longitudinally extendinglstrip; portions 304 terminating or; blending into-the" body of the sheet at opposite sides of the fold, line, whereby said central transverse portion of the sheet'is considerably weakened. Accordingly, when, a third fold C, is made in the combined twice foldedsheets S1, S2; at right angles to the twofoldsA and B previously made therein and said sheets have formed therein the s1its303, through, and extending in opposite directions across. the folded. edges of the folds Aland B, the. strip portions.304 twist slightly and thus 18 permit the outer and innerlayers of thelsheets to creep and adjust themselves at the folds A1 andB to the change in their relation elfected by the rightrangle foldiC, thereby eliminating crowding or bunchingof the innermost layers at the opposite corners of the right'angle fold C' intersecting the folds A and B whereupon wrinkling. 0ft said layers at said corners and. along the folds A and B is completely avoided. It will, be understood thatin producing the multi-fold thirty-two page signatures, either the relatively long slits 81, 258, or the relatively short slits 303 may be effectively employed, or, if desired, the. slits 303. may be formed injthe sheet S1 onthe line of the first fold and the slits 81 or 258 may. be formed; in the combined sheets, 51, S2 onthe line of the-second fold, or vice versa. It will also be understoodthat when producing multi-fold signatures, from single sheets asin existing types of folding machines, the described. method of crosswise slittingthe sheet on and along a fold preced-t ing a right angle, fold may be advantageously. employed to prevent wrinkles in the innermost leaves of 'the signa: tures. Basically, wrinkling of'the innermostwpages or leaves of a multi-fold signature is. prevented by dividing the folded edge of a fold preceding'a right angle fold into a plurality of narrow portions and; hence, the pres: ent invention comprehends forming the slits. 303' in the sheet through and crosswise of said folded edgeafter said precedingfold has been'made imthe sheet or sheets.

Suitable slitting mechanism isprovid'ed for forming the slits 303 in, the sheets S1 and 5.2 as previously described. .In the form shown in. Figs. 8 and 9, saidslitting mechanism comprises a transversely extending head 305 and a cooperatingtransversely extending. two-part. die plate 306 both of which maybe substitutedfor the die plate 38 and the head 99 forminggpa-rtgofthe slitting: mechanism shown in Figs. 1 and-2, and; for the die plate 249 and the head forming part of the slitting: mechansim 253 shown in Fig. 1a. For purposes ofillustration only, the head 305 and the die plate306ja-re shown a'sforming: part of the slitting mechanism shown in, Fig, l. Accordingly, the] head 305, is bolted, or: otherwise; suitably. secured at oppositeends thereo-fito;the brackets-981which, in turn, are bolted-or otherwise suitably SGGUIEdJtOHLhQ vertical slides 92, and the die plate 306 is :b'olted, 0.12: otherwise suitablysecured to the'cross bar 42;,

Formedon the underside f the head 305;;atopposite; endsithereof are depending lugs30 7' andlh-pr'ovided: with axially aligned openings; therein; Extending. throughthe-openings in the lugs307', 308 and supported by said lugs is a relatively. longtransversely extending rigid. rod: 309 which; isformed"; with an enlarged; head, 310 at one, end thereof and; is externally threaded; at; the opposite end thereof. Disposed] between; the lugs} 30.7; 308: and loosely engaged. over the rod? 309 are slitter blades 311 which are closely spaced in face to.

face relation and extendin the direction, of travel of,

the sheet S1 onthe tape conveyors 2,4,- 40; Each of; the blades 311 is formed with a sharpened V,-shaped; sheet piercing edge, and saidblades are held against rotation relative to the rod 309 through engagement; of; the upper square ends thereof-with, the underside, ofthe head 305; The blades 311 are maintained in spaced relation by. annular spacer collars}, 312 of equal widtht loosely engaged over the rod 309, and saidblades and: whats are immovably clamps together. and against the lug 307 by a nut 313 threaded onto the threaded end of: said rod. Spring controlled clamps 314' are carried; by; the head 305'at opposite sides thereof, said clampsgbe. ing turned away from the blades 311- to provide asp-ace therebetween for theoperation of said "blades. The die plate 306 is forrnedwith correspondingly. spaced slots 315 vertically aligned-with the blades 311 to receive the latter. i a

It will thus appear that when the head305 descends with the sheet S1 at rest on the tape conveyors 2 4,; 4,0, and engaged with the front, stops or gage-fingers 51,

the clamps 314 clamp said sheet against the die plate 306 and the blades 311 pierce the sheet and enter the slots 315 in said die plate, thus forming in the sheet a plurality of short slits 3.03 spaced along a transverse line in termediate the front and rear edges of said sheet and extending in opposite directions across said line and longitudinally of the sheet. When the head 305 rises, the clamps 314 first continue to bear on the slit sheet S1 and strip it from blades 311 whereupon said clamps rise with said head to release said sheet. Thereupon the stops or gage fingers are lowered and the slit sheet S1 is advanced into the folding machine for folding with a second sheet S2, as previously described, to produce a thirty-two page signature having a closed head and which is free of wrinkles on the inner leaves or pages thereof. The extent that the slits 303 project inwardly beyond the folded edges A and B of the signature and, hence, the length of said slits, depends upon and should not exceed the width of the trim allowed in the sheets for subsequent removal of said folded edges in the mak ing of books or magazines from a plurality of said signatures so that when the bound assembly of signatures is trimmed to book or magazine size at the head con taining the second fold B and at the foot containing the first fold A, the trimmed-off signature portions will contain the slits 303 in their entirety.

The present invention has been described and illustrated herein with more or less particularity in connection with an embodiment capable of producing signatures of thirty-two pages. It is to be expressly understood, however, that the present invention is not limited to said embodiment or to the specific type of folding machine disclosed herein. Various changes may be made in the mechanical details, and in the design and arrangement of the parts illustrated, as well as in the mode of operation, assembly, and manner of use, without departing from the spirit and scope of the invention, as will now be clear to those skilled in the art.

What is claimed is:

1. The method of producing multi-pa-ge signatures,

ch consists in feeding a first unfolded sheet, forming a plurality of short slits in and through said sheet at spaced intervals along substantially the entire length of a transverse line intermediate opposite extremities of the sheet, said slits extending from a point at one side of and adjacent to said line across said line and terminating at a point at the opposite side of and adjacent to said line and being separated from each other by unslit portions of said sheet, feeding a second unfolded sheet and associating it with said first a first fold to the associated sheets on said transverse line so that the slitted first sheet will be disposed outwardly of said second sheet, and thereafter imparting additional folds successively to the once-folded associated sheets, at angles to said first fold, said slits being adapted to Weaken said first sheet at said transverse line sufliciently to allow the outer and inner leaves of said first sheet folded on said transverse line to shift relatively and adapt themselves to the change in their relation when said right angle fold is made in the associated sheets, whereby the formation of wrinkles in the inner leaves of the resulting signature is avoided.

2. The method as defined in claim 1, which includes the steps of stopping said first unfolded sheet temporarily while said slits are formed therein, and thereafter further feeding the slitted first sheet for association with said second unfolded sheet.

3. The method of producing multi-page signatures, which consists in feeding a first unfolded sheet, forming a series of slits in and through said sheet spaced along the entire length of a transverse line centrally between opposite extremities of the sheet, feeding a second unfold-ed sheet and associating the same with said first sheet in register, imparting a first fold to the associated sheets sheet in register, imparting least one of said additional folds being at right on said transverse line and so that said second sheet Will'- be disposed within the slitted first sheet, further feeding the once-folded associated sheets, forming a series of slits in and through the four halves of the once-folded associated sheets spaced along the entire length of a second transverse line centrally between opposite ex- 'trernities of :the once-folded associated sheets and parallel with the first fold line, imparting a second fold to the associated sheets on said second transverse line and parallel with said first fold, and thereafter imparting a third fold to the associated sheets on a line at right angles to said first and second folds and centrally between opposite extremities of the associated sheets, said first and lastnamed slits being of such length so as to weaken said first sheet and the once-folded associated sheets at said first-named transverse line and said second transverse line, respectively, sufiicien-tly to allow the outer and inner leaves of the associated twice-folded sheets to shift relatively and adapt themselves to the change in their relation when said right angle fold is made therein, whereby the formation of wrinkles in the inner leaves of the resulting signature is avoided.

'4. The method as defined in claim 3, which includes the additional steps of stopping the first unfolded sheet temporarily while the slits are formed therein and thereafter further feeding the slitted first sheet for association with the second unfolded sheet, and stopping the once-folded associated sheets temporarily While the slits are formed in the four halves thereof and thereafter further feeding the once-folded and slitted associated sheets for the making of said second fold therein.

5. The method as defined in claim 3, wherein the slits of both said series are of substantial longitudinal extent and extend lengthwise of the respective fold lines and alternate with unslit sheet portions less than bnehalf the length of the slits.

6. The method as defined in claim 3, wherein the slits of both said series are relatively short and extend across the respective fold lines.

7. The method as defined in claim 3, wherein the slits of said first-named series are relatively short and extend crosswise of said first-named transverse line, and the slits of said second-named series are of substantial longitudinal extent and extend lengthwise of said second transverse line and alternate with unslit sheet portions less than onehalf the length of said latter slits.

8. 'In apparatus of the character described, means to which a sheet is fed and adapted to form a plurality of short slits in and through said sheet at spaced points along substantially the entire length of a line located intermediate opposite extremities of the sheet and extending transversely of said sheet from edge to edge of the latter, said slits beginning at one side of and adjacent to said line and ending at the other side of and adjacent to said line leaving unslit portions of said sheet between the same, means for folding said sheet on said line and through said slits, and means for further folding said sheet on a line disposed at right angles to said first-named line, said slits enabling the outer and inner leaves of the sheet folded on said first-named line to relatively adaptthemselves to the change in their relation when folded on said second-named line, whereby wrinkles in the inner leaves of the resulting signature are avoided.

9. In apparatus of the character described, means to which a sheet is fed and adapted to form a plurality of aligned short slits in and through said sheet spaced transversely of its direction of feed and extending in and parallel to said direction leaving unslit portions of said sheet between the same, means for folding said sheet on a transverse line passing through said slits, and means for further folding said sheet on a line disposed at right angles to said transverse line, said slits enabling the outer and inner leaves of the sheet folded on said transverse line to relatively adapt themselves to the change in their relation when folded on said second-named line, whereby wrinkles in. the inner; leaves; of the" resulting signature are avoided.

In: apparatus of the character described, means for feeding a, sheet, slitting means and folding means to which said-sheet is. fed, by-said feeding means, said slittingrmeansbeingadapted' to forma plurality of aligned short! sl-itsin; and through said sheet spaced transversely of its direction of'feed' and extending in and parallel to said direction leaving unsli-t portions: of said sheet between the same, and said folding means being adapted to fold saidsheet on a transverse line passing through said slits centrally'between-thei opposite ends-thereof, and means for further fold-ing said sheet on .a line disposed atri'ghtangles tosa-idtransverse line, said slits enabling the outer and inner "leaves of the sheet folded on said transverse line to relativelyadapt themselves to the change in tlieir relation-when folded on said second-named line, whereby-wrinklesthe inner leaves of the resulting signature are avoided.

' 11, ln-apparatusof-the character described, means for temporarily stopping a travelling sheet, means operative While said-sheetis so'stoppedfor forming a plurality of aligned short slits therein spacedtransversely of its direction; of'traveland extendinginand'parallel to said direction and through saidsheet; the portions of said sheet between said slits being unslit, means for thereafter folding-said sheet on a transverse line passing through said slits centrallybetween the opposite ends thereof, means forfurther. folding said sheet on a line disposed at right a gles to said transverseline, said slits enabling the-outer and inner leaves of the sheet folded on said transverse line to relativelyadapt themselves to the change in their relation when folded on said second-named line, whereby wrinkles in the inner leaves of the resulting signature are avoided.

12. Apparatus as defined in claim ll, wherein said sheet slitting means comprises a reciprocal head extending transversely of the direction of travel of the sheet, a

- plurality of flat .slitter blades disposed substantially at right angles to the leading edge of said sheet and carried at one end thereof by said head in spaced face to face relation, each of said blades having the opposite free end thereof formed to provide a relatively sharp V-shaped sheet piercing edge, and means for reciprocating said head and said blades.

'13. In apparatus of the character described, conveyor means disposed at a lower level for advancing an unfolded sheet in a horizontal plane, a pair of [cooperating folding rollers arranged below said plane and extending transversely of the direction of travel of said sheet over which said sheet is advanced by said conveyor means, a reciprocal folding knife arranged above said plane and cooperating with said folding rollers to fold said sheet, and other conveyor means disposed at an upper level for advancing a second unfolded sheet beneath said knife in the same direction as said first-named sheet so that it overlies said first-named sheet for folding simultaneously therewith by said knife and said rollers, said other conveyor means comprising angular-1y related sections disposed at opposite sides of said knife, one of said sections being inclined upwardly and forwardly from said plane toward said knife, and the other of said sections being inclined upwardly and reanwardly from said plane toward said knife.

14. Apparatus as defined in claim 13, including a side gage disposed at said lower lever adjacent one side of said first-named conveyor means, a separate side gage disposed at said upper level adjacent the same side of said other conveyor means, and means engageable with the over and underlying sheets on said conveyor means inwardly of the side edges thereof adjacent said side gages for moving said sheets simultaneously and independently of each other laterally into position against said side gages.

115. la apparatus of the character described, sheet fold- 22 ing mechanism including; a: pairi of: cooperating; rollers and a cooperating reciprocal knife,,and conveyor-means for advancing a'sheet between said knife and: said-rollers:

for folding thereby transversely. to itsdirection of travel; said conveyor means comprisingaa downhill endless; tape section at the rear side of saidkni-fe and-an uphil-Lendless tape section at the f-rontsi-de, ofsaid knife, and gagestop means associated with said' uphill .endlesstapefsection for arresting the forward movement of said; sheet and locating the same in proper. longitudinal positionforv folding by said knife and said rollers. i

16. in apparatus of the character described, a. twoz-z sheet side registering device comprising two normally fixed: independently adjustable side gages extending to differ.-

ent levels,.a bracketreciprocal toward and awayfrom.

said side gages, a gripper carried by and movable with said bracket adapted to grip a sheet on one of said: levels and draw the same into engagement with the side gage at the said one level, and asecond gripper carried by. and movable with said bracketv adapted to simultaneously grip a second sheet onthe otherofisaid levels and draw the same into engagement with thes-ide gage at the said other level.

17. -A two-sheet registering device comprising. a. reciprocal bracket, two fixed lower gripper jaws onisaid bracket disposed atupper and lowerlevels respecti vely, a first upper gripper jaw lever pivotally mounted on said bracket, a-second upper gripper jaw lever pivotally mounted on said bracket in coaxial relation with said first lever, said first lever extending. intorlcooperative relation with the fixed lower level gripper jawz-andsaid second lever extending into cooperative relation with the fixed upper level gripper jaw and having a portion thereof disposed over and engageable by said first lever, re

ting like movement to be imparted to said second lever by said resilient means.

18. In the art of folding a sheet a plurality of times to produce a multi-pa-ge signature product wherein one of the folds is disposed at right angles to a preceding fold, the method of avoiding the formation of wrinkles in the inner leaves of said signature product comprises forming in and through the sheet on and at spaced intervals along substantially the entire length of the line of said preceding fold and prior to making said right angle fold a plurality of short slits, said slits extending from a point at one side of and adjacent to said line across said line and terminating at a point at the opposite side of and adjacent to said line and being separated from each other "by unslit portions of said sheet, whereby the continuity of said sheet is maintained and the outer and inner leaves resulting from said preceding fold may relatively adapt themselves to the change in their relation when said right angle fold is made therein.

19. In the art of folding a sheet a plurality of times to produce a multinpage signatureproduct wherein one of the folds is disposed at right angles to a preceding fold, the method of avoiding the formation of wrinkles in the inner leaves of said signature product which comprises forming in and through the sheet on and at spaced intervals along substantially the entire length of the line of said preceding fold and prior to making said preceding fold a plurality of short slits, said slits extending from a point at one side of and adjacent to said line across said line and terminating at a point at the opposite side of and adjacent to said line and being separated from each other by unslit portions of said sheet, whereby the continuity of said sheet is maintained and the outer and inner leaves resulting from said preceding zfold may relatively adapt themselves to the change in their relation when said'right angle hold is made therein.

-20. In the art of folding a sheet to produce a multipage signature product consisting-of two successive parallel rfolds followed by a right angle fold, the method of avoiding the formation of :wrinkles in the inner leaves of said signature product Which comprises iforming in and through the sheet on and at spaced intervals along substantially the entire length of the line of the second parallel fold a plurality of short slits, said slits extending from a point at one side of and adqacent to said line across said line and terminating at a point at the opposite side of and adjacent to said line and being separated from'ea'ch other 'by unslit portions of said sheet, whereby the continuity of said sheet is maintained and the outer and inner leaves of the twice-folded sheet may relatively adapt themselves to the change in their relation whensaid right angle told is made therein.

'21. In the art of folding .a sheet to produce a multipage signature product consisting of two successive parallel folds followed :by a right angle fold, the method of avoiding the formation of wrinkles in the inner leaves of said signature product which comprises lforming in and through the sheet on and .at spaced intervals along substantially the entire length of the line of the first liold and prior to making said latter told and on and at spaced intervals along substantially the entire length of the line of the second (fold and prior to making said latter told a plurality of short slits, said slits extending (from a point at one side of and adjacent to said lines across said References Cited in the file of this patent UNITED STATES PATENTS 396,308 Stonemetz Jan. 15, 1889 456,597 'Remus July 28, 1891 826,998 Dexter July 24, 1906 1,326,859 Grammer Dec. 30, 1919 1,326,860 Grammer Dec. 30, 1919' 1,551,142 Franz Aug. 25, 21925- 1,793,552 Kast Feb. 24, 19-3l1 2,011,572 Eisman Aug. 20, '1935 2,018,855 Irns'hang Oct. 29, 1935 2,069,211 Brown Feb. 2, 19 317 2,1 14,108 Hormel AprmlQ, 1938 2,118,964 'Bonnaire Apr. 26, 1938 2,129,569 Danielson Sept. 6, 1938, 2,167,823 Backhouse Aug. I1, 1939 2,176,815 Hirohashi Oct. 17, 19 39 2,211,3110 Andrews Aug. 1 3, 1940 2,232,152 Tufts et a1 Feb. 18, 1941 2,383,569 Higgins Nov. 2, 1943 2,627,427 Weimont Feb. 3, '1956 

